I agree with pgrzes has this always been a issue or just started happening your pressure of 200psi is good. If your tree is in the equipment room and your bridge machine is 2-3 bays over it will take a little longer to deliver product. You got some check valves bad somewhere more than likely i would check every one on the tree and check the foam in the tree make sure its good and check all your spray tips make sure there all clean and clear if 2-3 tips are restricted it will cause a delivery issues as well